This invention pertains to wireless communications, particularly related to any wireless systems which consist of a group of base stations (BTSs) with smaller coverage areas in order to cover a larger coverage areas, or co-existence of a group of BTSs with smaller coverage areas and BTSs with larger coverage areas. One specific example is a Femtocell or Pico cell network and base station system. In the following description, even though we describe the system using certain examples, it should be noted that all the techniques can be used in any other BTS systems with similar properties, including but not limited to Femtocell, Pico cell, WiFi access points and so on.
Referring to FIG. 1, a Femtocell 110a or 110b is a smaller cellular base station or access point having a coverage area or foot print 112a and 112b that operates in either licensed frequencies, or if so desired, in unlicensed frequencies. A Femtocell uses the available broadband access 114a and 114b, such as DSL, cable, fiber optics, or fixed wireless broadband access networks, to tunnel the user data (from user equipment devices (UEs) such as a cellular telephone or other device capable of wirelessly communicating with the base station 110a or b) and control data through the broadband connection and connect to the cellular core network backhauls. An example of such an arrangement is illustrated in FIG. 1.
The current Femtocell systems described above have a number of problems that arise due to the fact they are more of a consumer device than a traditional base station, and therefore the operator provisioning, or rather lack of it, and make the deployment and maintenance very difficult and not cost effective, if not impossible.
US patent application 20070254620 “Dynamic Building of Monitored Set” tried to address difficulties in handover due too many neighboring cells in a Femtocell environment as well as handover from the macro network to Femtocells. It proposed for the Femtocell radio base station node to comprise a receiver for receiving scanned cell information and a reporting unit providing the scanned cell information to the radio network control node. Even though the description introduced an additional receiver in the Femtocell, it is only used to scan channel information using the same air-interface as the Femtocell transceiver. It didn't enable the full functional over-the-air communications between the Femtocells and macro cell or among the Femtocells. Further more, due to the above limitations, the system is still very limited in addressing neighboring cell search related issues and it didn't address issues of interference management, security, registration, authentication, scheduling and QoS, location, etc.
US patent application 20080076392 “METHOD AND APPARATUS FOR SECURING A WIRELESS AIR INTERFACE” proposed communication between the Femtocell and macro networks through an Iu interface or equivalent for the purpose of registration, handover and so on. It does not have any over-the-air communications between the Femtocells and macro cells, and among the macro cells. Furthermore, it doesn't address issues related to interference management, security, registration, authentication, scheduling and QoS, location, etc.
US patent application 20080096553 “MOBILE COMMUNICATION NETWORK” described a method of creating a unified wireline/wireless communication network. It does not have any over-the-air communications between the Femtocells and macro cells, and among the macro cells. Furthermore, it doesn't address issues related to interference management, security, registration, authentication, scheduling and QoS, location, etc.
US patent applications 20080081636 “ACCESS CONTROL SYSTEM, METHOD, AND ARRANGEMENT IN A WIRELESS COMMUNICATION NETWORK”, 20070270152 “ACCESS CONTROL IN A MOBILE COMMUNICATION SYSTEM”, and 20070270152 “ACCESS CONTROL IN A MOBILE COMMUNICATION SYSTEM” all cope with the subject of access control for Femtocells. The basic idea is to build a database for access control. It does not have any over-the-air communications between the Femtocells and macro cells, and among the macro cells. Furthermore, it doesn't address issues related to interference management, security, registration, authentication, scheduling and QoS, location, etc.